The reason economics is so difficult to understand . . . ​

This really is simple. You trade with your grocery store, it does not trade with you. Should you require it to have a balanced trade account with you? No, that would be idiotic. You trade your labor with your employer. Does your employer have a balanced trade account with you? No. Again this requirement would be idiotic. Ultimately, trade must be balanced. That means that money must flow back into the US just as you must have money flow into your bank account to continue purchasing things from your grocery store. In international trade this commonly occurs through investment. In the case of the US/China it means that the Chinese use US dollars to buy assets, entities, and other valuable things in the US. We call this investment.

Evil men have long felt threatened by others, from foreign lands, who often have different colored skin, and speak funny languages. They want you to believe that these others are stealing your wealth. How? By selling you something you find more dear than the pittance in money you give them. It is not just Trump who believe this, but Hillary Clinton, and Bernie Sanders as well.

The crime is that we occasionally believe these foolish, and evil men, and women. Do not be fooled, eschew all those who would demagogue trade, and never fall for the trap that free trade is somehow bad for the US, or our trading partners.